A load-capacity interference model for common-mode failures in 1-out-of-2:G systems

Load-capacity (stress-strength) interference theory is used to model the ti me-dependent behavior of a 1-out-of-2: G redundant system and to examine co mmon-mode failures. For single units subjected to Poisson distributed load arrivals, the random failures, infant mortality, and aging are associated w ith load variability, capacity variability, and capacity deterioration, res pectively. This paper extends the analysis to a redundant system by using a Markov model to treat Poisson distributed loads arriving at units simultan eously. Loss of a-independence of the unit failures is analyzed with joint pdfs of load and capacity. In the rare-event approximation, the degree of r edundancy loss is characterized by expressing the coefficient in the beta-f actor method in terms of the load and capacity distributions.